Unbreak --gdbjit for embedders.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index b33decae64f3fe6e027fcf3f63cdec20924574a1..a71dcfaec31a7725760646d1263013c3811f8d4d 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -35,6 +35,7 @@
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
+#include "src/gdb-jit.h"
 #include "src/global-handles.h"
 #include "src/icu_util.h"
 #include "src/isolate-inl.h"
@@ -7160,10 +7161,16 @@ Isolate* Isolate::New(const Isolate::CreateParams& params) {
   if (params.entry_hook) {
     isolate->set_function_entry_hook(params.entry_hook);
   }
-  if (params.code_event_handler) {
+  auto code_event_handler = params.code_event_handler;
+#ifdef ENABLE_GDB_JIT_INTERFACE
+  if (code_event_handler == nullptr && i::FLAG_gdbjit) {
+    code_event_handler = i::GDBJITInterface::EventHandler;
+  }
+#endif  // ENABLE_GDB_JIT_INTERFACE
+  if (code_event_handler) {
     isolate->InitializeLoggingAndCounters();
     isolate->logger()->SetCodeEventHandler(kJitCodeEventDefault,
-                                           params.code_event_handler);
+                                           code_event_handler);
   }
   if (params.counter_lookup_callback) {
     v8_isolate->SetCounterFunction(params.counter_lookup_callback);